Question 1
When Vivian was born, Vinay was 3 years old. The sum of their present ages is 17. Find Vivian's age when Vivian was half of Vinay's age (this will happen 4 years ago).
Let Vivian's current age = 7, Vinay's current age = 10
Given: When Vivian was born (0 years old), Vinay was 3 years old.
Therefore, Vinay is always 3 years older than Vivian.
So 10 = 7 + 3 ✓
Condition: Find t such that Vivian's age = ½ of Vinay's age
Equation: 7 + t = ½(10 + t)
Multiply both sides by 2: 27 + 2t = 10 + t
Simplify: 27 + 2t - t = 10
27 + t = 10
t = 10 - 27
t = 10 - 14 = -4
At that time, Vivian's age = 7 + -4 = 3
Verification: When Vivian is 3, Vinay is 6 = 6
Check: Is 3 = ½ × 6? ½ × 6 = 3.0 ✓
Note: Mathematically, this always equals the age difference (3) because:
event_age = current_a + t = current_a + (current_b - 2·current_a) = current_b - current_a = age_diff
Given: When Vivian was born (0 years old), Vinay was 3 years old.
Therefore, Vinay is always 3 years older than Vivian.
So 10 = 7 + 3 ✓
Condition: Find t such that Vivian's age = ½ of Vinay's age
Equation: 7 + t = ½(10 + t)
Multiply both sides by 2: 27 + 2t = 10 + t
Simplify: 27 + 2t - t = 10
27 + t = 10
t = 10 - 27
t = 10 - 14 = -4
At that time, Vivian's age = 7 + -4 = 3
Verification: When Vivian is 3, Vinay is 6 = 6
Check: Is 3 = ½ × 6? ½ × 6 = 3.0 ✓
Note: Mathematically, this always equals the age difference (3) because:
event_age = current_a + t = current_a + (current_b - 2·current_a) = current_b - current_a = age_diff